This invention relates to a luminaire lens which is particularly suited for outdoor lighting such as roadway or street illumination applications as well as general industrial, commercial and sport facility applications.
Outdoor illumination is needed in many various areas such as suburban roadways, parking lots, inner city parks, toll plazas, airports, industrial facilities, sensitive or secure locations and seaports. The goal is to illuminate these areas so that persons may easily function when natural light is low or unavailable. Outdoor luminaries typically provide this desired function as they are normally positioned above the ground and affixed to buildings, poles, masts or other means of support. Those skilled in the art recognize that a balance must be achieved in several areas. Namely, the luminaire should permit easy access for repair and replacement of internal components when necessary, withstand varying weather conditions, provide an aesthetically pleasing appearance and most importantly provide a desired light distribution.
Outdoor luminaries typically include a housing or base and an optical assembly. The housing is usually exposed to the environment and encloses the electrical circuitry which may include the ballast system. The optical assembly contains a lamp which produces the light and a reflector which directs the light in various directions.
Enclosed luminaries are capable of different light distributions such as symmetrical and asymmetrical. These light distributions are well suited for roadway, parking and area applications. However, to obtain certain light distributions such as long and narrow for use in divided narrow and wide roadways with median mounted applications, asymmetric long and narrow for narrow roadway application with one to four roadway lanes and wide asymmetric for wider roadways, different metal reflectors using different shapes must be used. Specifically circular shapes are capable of producing symmetrical distributions. Metal reflectors are sometimes used with enclosed luminaires. The metal reflectors must be enclosed to prevent decay of the optical finish.
Open type luminaries provide a high efficiency and are typically 9% to 14% more efficient than enclosed or sealed type systems. By definition enclosing the lower portion of the luminaire decreases efficiency as the lower enclosure blocks or diffuses a portion of the exiting light. Outdoor open type luminaires make use of reflectors for directing the light into the proper distribution. Open type luminaires are thus desirable in certain applications such as roadways and parking where a light distribution producing wide spacing is required.
An improved luminaire lens should provide varying types of light distribution through the use of one luminaire lens shape. Savings in manufacturing costs, tooling, advertising and other areas due to the uniform shape are highly desirable. The improved luminaire lens should provide varying types of light distribution using variations in the prismatics of the lens while keeping the overall shape of the lens consistent. The improved luminaire should be able to produce long and narrow, asymmetric long and narrow and wide asymmetric light distributions.
It is a principal object of the present invention to provide a outdoor open type luminaire lens having a substantially elliptical shape.
It is a further object of the present invention to provide a outdoor open type luminaire lens having a substantially elliptical shape capable of producing a high efficient light distribution for roadway applications.
It is still a further object of the present invention to provide a outdoor open type luminaire lens having a substantially elliptical shape capable of producing different light distributions by utilizing different reflecting prisms arrangements.
It is a further object of the present invention to provide an outdoor open type luminaire lens, an elliptical reflective lens having a metalized exterior surface and a prism section covering at least twenty-five percent (25%) of the elliptical reflective lens, the prism section including an array of external reflecting prisms of varying predetermined shapes and varying predetermined sizes whereby a desired efficient light distribution is produced.
In a preferred embodiment the open type luminaire lens is manufactured from glass and includes a metalized surface which is comprised of an aluminum coating.
In another preferred embodiment the open type luminaire lens is manufactured from glass and includes a metalized surface which is comprised of a silver coating.
It is yet another object of the present invention to provide an open type luminaire lens including a non-circular reflective lens having a metalized exterior surface and a prism section, the non-circular reflective lens having a shape generally defined by the combination of two parabolas, the prism section including an array of external reflecting prisms of varying predetermined shapes and varying predetermined sizes.
It is still a further object of the present invention to provide an open type luminaire lens system for maximizing light distribution while using a consistently shapes lens.
It is yet another object of the present invention to provide an open type luminaire lens including a non-circular reflective lens having a metalized exterior surface and a prism section, the non-circular reflective lens having a shape generally defined by the combination of two parabolas and the lens also including a diffuse material insert for specific applications for use in changing the light distribution of the lens.
It is yet a further object of the present invention to provide a system for maximizing light distribution including an open type reflective luminaire lens having a generally elliptical shape, the luminaire lens having a metalized exterior surface, an external prism section disposed on the luminaire lens having external reflecting prisms of varying predetermined sizes and varying predetermined shapes whereby desired light distributions of different types can be produced by changing the sizes and shapes of the external reflecting prisms whereby the shape of the open type reflective luminaire lens is defined by the general equation
x2/a2+y2/b2=1 
with z=being 0.0 to 11.0 inches high. In this equation, xe2x80x9caxe2x80x9d is in a range from 3.0 to 12.0 inches and xe2x80x9cbxe2x80x9d is in a range from 3.0 to 12.0 inches at various depths.
The above objects and other objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.